Is there a way to move a view around a center point without rotating it using the view animations?
A
A C A
A
#import <QuartzCore/QuartzCore.h>
#define degreesToRadians(deg) (deg / 180.0 * M_PI)
manualy :
-(CGPoint)setPointToAngle:(int)angle center:(CGPoint)centerPoint radius:(double)radius
{
return CGPointMake(radius*cos(degreesToRadians(angle)) + centerPoint.x, radius*sin(degreesToRadians(angle)) + centerPoint.y);
}
with animation something like this:
int angle = 0; // start angle position 0-360 deg
CGPoint center = self.view.center;
CGPoint start = [self setPointToAngle:angle center:center radius:radius]; //point for start moving
CGMutablePathRef path = CGPathCreateMutable();
CGPathMoveToPoint(path, NULL, start.x, start.y);
for(int a =0;a<4;a++) //set path points for 90, 180, 270,360 deg form begining angle
{
angle+=45;
expPoint = [self setPointToAngle:angle center:center radius:expRadius];
angle+=45;
start = [self setPointToAngle:angle center:center radius:radius];
CGPathAddQuadCurveToPoint(path, NULL,expPoint.x, expPoint.y, start.x, start.y);
}
CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:#"position"];
pathAnimation.removedOnCompletion = NO;
pathAnimation.path = path;
[pathAnimation setCalculationMode:kCAAnimationCubic];
[pathAnimation setFillMode:kCAFillModeForwards];
pathAnimation.duration = 14.0;
[MY_VIEW.layer addAnimation:pathAnimation forKey:nil];
also look at
CGPathAddQuadCurveToPoint,
CGPathAddCurveToPoint,
CGPathAddArcToPoint,
CGPathAddArc
and others
Its not that big a deal to put an animation thread in and move it manually every frame so thats what I went with.
Related
I am making an iPhone app that draws a circle on the screen. I use a timer (every 5 second), so that I can 'grow' the circle, then wait 5 seconds then grow again. Now I am having trouble when animating the increase in size of the circle (I use paths and a CAShapeLayer layer). The size (from and to) are fine with the animation, its just when it starts the circle moves to the upper left hand side and grows from there. Any help or suggestions would be great. Thanks
The class where this is implemented is a UIControl, which is added to a UIView.
//Called in init method
(void) initalPop {
//Circle
self.bubble = [CAShapeLayer layer];
self.bubble.bounds = self.bounds;
self.bubble.position = CGPointMake(CGRectGetMidX(self.bounds), CGRectGetMidY(self.bounds));
self.bubble.fillColor = [
[UIColor greenColor] CGColor
];
self.bubble.strokeColor = [
[UIColor greenColor] CGColor
];
self.bubble.lineWidth = 4.0;
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddEllipseInRect(path, nil, self.bounds);
self.bubble.path = path;
[self.layer addSublayer: self.bubble];
}
//Called when timer goes off
- (void) StageGrow {
CGFloat growSize = 50.0;
//Change the size of us and center the circle (but dont want to animate this
[CATransaction begin];
[CATransaction setValue: (id) kCFBooleanTrue forKey: kCATransactionDisableActions];
self.bounds = CGRectMake(0, 0, self.bounds.size.width + growSize, self.bounds.size.height + growSize);
self.bubble.position = CGPointMake(CGRectGetMidX(self.bounds), CGRectGetMidY(self.bounds));
[CATransaction commit];
[self ActualGrowCircle];
} - (void) ActualGrowCircle {
CGMutablePathRef oldPath = CGPathCreateMutable();
CGPathAddEllipseInRect(oldPath, nil, self.bubble.bounds);
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddEllipseInRect(path, nil, self.bounds);
CABasicAnimation * animation = [CABasicAnimation animationWithKeyPath: #"path"];
animation.duration = 2.0;
animation.timingFunction = [CAMediaTimingFunction functionWithName: kCAMediaTimingFunctionEaseInEaseOut];
animation.repeatCount = 1;
animation.delegate = self;
animation.autoreverses = NO;
animation.fromValue = (__bridge id) oldPath;
animation.toValue = (__bridge id) path;
self.bubble.bounds = self.bounds;
self.bubble.path = path;
[self.bubble addAnimation: animation forKey: #"animatePath"];
}
Let's say you're growing the bubble from size (100, 100) to size (150, 150).
You create oldPath as an ellipse in the rectangle (0, 0, 100, 100).
You create path as an ellipse in the rectangle (0, 0, 150, 150).
You set the bounds of the bubble layer to (0, 0, 150, 150), and you don't animate this change.
That means that oldPath will appear aligned to the top and left edges of the bubble layer.
One way to fix this is to create oldPath in a rectangle that is centered in the bubble's new bounds:
CGRect oldBubbleRect = CGRectInset(self.bounds, growSize / 2, growSize / 2);
CGPathRef oldPath = CGPathCreateWithEllipseInRect(oldBubbleRect, NULL);
By the way, you are leaking the paths you're creating. You need to call CGPathRelease on them after you're done with them.
Worked it out. In the long run I grouped the animations together and all became good (see code below). Thanks for your help Rob.
-(void)ActualGrowCircle {
CGMutablePathRef newPath = CGPathCreateMutable();
CGPathAddEllipseInRect(newPath, nil, self.bounds);
CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:#"path"];
animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
animation.repeatCount = 1;
animation.autoreverses = NO;
animation.fromValue = (__bridge id)self.bubble.path;
animation.toValue = (__bridge id)newPath;
CABasicAnimation *animation2 = [CABasicAnimation animationWithKeyPath:#"bounds"];
animation2.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
animation2.repeatCount = 1;
animation2.autoreverses = NO;
animation2.fromValue = [NSValue valueWithCGRect:self.bubble.bounds];
animation2.toValue = [NSValue valueWithCGRect:self.bounds];
CAAnimationGroup *group = [CAAnimationGroup animation];
[group setAnimations:[NSArray arrayWithObjects: animation2, animation, nil]];
group.duration = 0.5;
group.delegate = self;
self.bubble.bounds = self.bounds;
self.bubble.path = newPath;
[self.bubble addAnimation:group forKey:#"animateGroup"];
CGPathRelease(newPath);
}
I am developing a small game in iphone... Game concept is place an object in top of the bar...Rotating a bar using accelerometer. When bar rotating , i need to move an object with respect to bar. How to implement this concept...Any examples or references?
Rotating both img:
barImg,objImg //UIImageView
barImg.transform = CGAffineTransformMakeRotation(Ypos);
objImg.transform=CGAffineTransformMakeRotation(Ypos);
So for rotating 360 Degree with animation:
CABasicAnimation *rotationAnimation;
rotationAnimation = [CABasicAnimation animationWithKeyPath:#"transform.rotation.z"];
rotationAnimation.toValue = [NSNumber numberWithFloat:-M_PI * 2.0]; // full rotation*/ * rotations * duration ];
rotationAnimation.duration = 1;
rotationAnimation.cumulative = YES;
rotationAnimation.repeatCount = MAXFLOAT;
[rotatingTelIamgeview.layer addAnimation:rotationAnimation forKey:#"rotationAnimation"];
you can play with toValue for changing the angle.
For moving an object:
CGPoint startPoint = CGPointMake(lvMessageInputBar.animationBubbleImageView.layer.frame.origin.x+lvMessageInputBar.animationBubbleImageView.layer.frame.size.width/2
, lvMessageInputBar.animationBubbleImageView.layer.frame.origin.y +lvMessageInputBar.animationBubbleImageView.layer.frame.size.height/2 );
CGPoint endPoint = CGPointMake(endPoint.origin.x+Endpoint.size.width/2, bubleRect.origin.y+bubleRect.size.height/2);
CGPoint middlePoint = // any point between start and end corrdinates
CGMutablePathRef path = CGPathCreateMutable();
CGPathMoveToPoint(path, NULL, startPoint.x, startPoint.y);
CGPathAddQuadCurveToPoint(path, NULL,middlePoint.x, middlePoint.y,endPoint.x,endPoint.y);
CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:#"position"];
pathAnimation.delegate = self;
pathAnimation.removedOnCompletion = NO;
pathAnimation.path = path;
[pathAnimation setCalculationMode:kCAAnimationCubic];
[pathAnimation setFillMode:kCAFillModeForwards];
pathAnimation.duration = 0.3;
[lvMessageInputBar.animationBubbleImageView.layer addAnimation:pathAnimation forKey:nil];
The above example moves the layer of the object over a path.but CGPathAddQuadCurveToPoint makes the path not diagonal rather circular path (curve).
you can use CGPathAddPath if you do not want this effect.
If you are new to iPhone I would start with layer tutorial to get the idea behind CALayer and then take a look CALayer animations
CALayers introduction:
https://www.raywenderlich.com/3096-calayers-tutorial-for-ios-introduction-to-calayers
CALayer Animation documentation of from Apple:
https://developer.apple.com/library/archive/documentation/Cocoa/Conceptual/CoreAnimation_guide/Introduction/Introduction.html
You can also watch Session 424 (Core Animation in Practice, Part 1) and 425 (Core Animation in Practice, Part 2) of WWDC 2010:
https://developer.apple.com/videos/archive/
I've managed to get along using [UIView animateWithDuration... to get animations done that I need in my UI. Now I want to move an image along a curved path, and that whole CAAnimation cluster looks pretty daunting to me.
I'd be much obliged if someone could help me fill in the method I wish I could code, which would look like this:
- (void)makeAnImageFlyFrom:(UIImageView *)imageViewA to:(UIImageView *)imageViewB alongPath:(CGMutablePathRef)path duration:(NSTimeInterval)duration {
UIImage *imageToFly = imageViewA.image;
// magic, that i'm too lazy to learn right now goes here
// image flys along the path and gets scaled to match imageViewB.
// then view/layer hierarchy is just as it was, but imageViewB has a new image
// maybe this happens on animationDidStop...
imageViewB.image = imageToFly;
}
Feel free to replace params (like path ref) if you think there's a smarter interface for this kind of method. Thanks in advance.
Ok, a whole Sunday later, here's a method that I think works. I'm still unclear about a few things, noted in comments, but if you need this type of thing, feel free to cut and paste. I promise not call you lazy:
- (void)makeAnImageFlyFrom:(UIImageView *)imageViewA to:(UIImageView *)imageViewB duration:(NSTimeInterval)duration {
// it's simpler but less general to not pass in the path. i chose simpler because
// there's a lot of geometry work using the imageView frames here anyway.
UIImageView *animationView = [[UIImageView alloc] initWithImage:imageViewA.image];
animationView.tag = kANIMATION_IMAGE_TAG;
animationView.frame = imageViewA.frame;
[self addSubview:animationView];
// scale
CABasicAnimation *resizeAnimation = [CABasicAnimation animationWithKeyPath:#"bounds.size"];
[resizeAnimation setFromValue:[NSValue valueWithCGSize:imageViewA.bounds.size]];
[resizeAnimation setToValue:[NSValue valueWithCGSize:imageViewB.bounds.size]];
// build the path
CGRect aRect = [imageViewA convertRect:imageViewA.bounds toView:self];
CGRect bRect = [imageViewB convertRect:imageViewB.bounds toView:self];
// unclear why i'm doing this, but the rects converted to this view's
// coordinate system seemed have origin's offset negatively by half their size
CGFloat startX = aRect.origin.x + aRect.size.width / 2.0;
CGFloat startY = aRect.origin.y + aRect.size.height / 2.0;
CGFloat endX = bRect.origin.x + bRect.size.width / 2.0;
CGFloat endY = bRect.origin.y + bRect.size.height / 2.0;
CGFloat deltaX = endX - startX;
CGFloat deltaY = endY - startY;
// these control points suited the path i needed. your results may vary
CGFloat cp0X = startX + 0.3*deltaX;
CGFloat cp0Y = startY - 1.3*deltaY;
CGFloat cp1X = endX + 0.1*deltaX;
CGFloat cp1Y = endY - 0.5*deltaY;
CGMutablePathRef path = CGPathCreateMutable();
CGPathMoveToPoint(path, NULL, startX, startY);
CGPathAddCurveToPoint(path, NULL, cp0X, cp0Y, cp1X, cp1Y, endX, endY);
// keyframe animation
CAKeyframeAnimation *keyframeAnimation = [CAKeyframeAnimation animationWithKeyPath:#"position"];
keyframeAnimation.calculationMode = kCAAnimationPaced;
keyframeAnimation.fillMode = kCAFillModeForwards;
keyframeAnimation.removedOnCompletion = NO;
keyframeAnimation.path = path;
// assuming i need to manually release, despite ARC, but not sure
CGPathRelease(path);
// a little unclear about the fillMode, but it works
// also unclear about removeOnCompletion, because I remove the animationView
// but that seems to be insufficient
CAAnimationGroup *group = [CAAnimationGroup animation];
group.fillMode = kCAFillModeForwards;
group.removedOnCompletion = NO;
[group setAnimations:[NSArray arrayWithObjects:keyframeAnimation, resizeAnimation, nil]];
group.duration = duration;
group.delegate = self;
// unclear about what i'm naming with the keys here, and why
[group setValue:animationView forKey:#"animationView"];
[animationView.layer addAnimation:group forKey:#"animationGroup"];
}
// clean up after like this
- (void)animationDidStop:(CAAnimation *)theAnimation finished:(BOOL)flag
{
UIImageView *imageViewForAnimation = (UIImageView *)[self viewWithTag:kANIMATION_IMAGE_TAG];
// get the imageView passed to the animation as the destination
UIImageView *imageViewB = (UIImageView *)[self viewWithTag:kDEST_TAG];
imageViewB.image = imageViewForAnimation.image;
[imageViewForAnimation removeFromSuperview];
}
I have been trying for the last few days to create the ken burns effect using a CALayer with animations and then save it to a video file.
I have my image layer which is inside another layer that is 1024x576. All of the animations are applied to the image layer.
Here is the code so far:
- (CALayer*)buildKenBurnsLayerWithImage:(UIImage *)image startPoint:(CGPoint)startPoint endPoint:(CGPoint)endPoint fromScale:(float)fromScale toScale:(float)toScale
{
float calFromScale = fromScale + 1;
float calToScale = toScale + 1;
float fromX = startPoint.x * calFromScale;
float fromY = (image.size.height * calFromScale) - (videoSize.height + (startPoint.y * calFromScale));
float toX = endPoint.x * calToScale;
float toY = (image.size.height * calToScale) - (videoSize.height + (endPoint.y * calToScale));
CGPoint anchor = CGPointMake(0.0, 0.0);
CALayer* imageLayer = [CALayer layer];
imageLayer.contents = (id)image.CGImage;
imageLayer.anchorPoint = anchor;
imageLayer.bounds = CGRectMake(0.0, 0.0, image.size.width, image.size.height);
imageLayer.position = CGPointMake(image.size.width * anchor.x, image.size.height * anchor.y);
imageLayer.contentsGravity = kCAGravityResizeAspect;
// create the panning animation.
CABasicAnimation* panningAnimation = [CABasicAnimation animationWithKeyPath:#"position"];
panningAnimation.fromValue = [NSValue valueWithCGPoint:CGPointMake(-fromX, -fromY)];
panningAnimation.toValue = [NSValue valueWithCGPoint:CGPointMake(-toX, -toY)];
panningAnimation.additive = YES;
panningAnimation.removedOnCompletion = NO;
// create the scale animation.
CABasicAnimation* scaleAnimation = [CABasicAnimation animationWithKeyPath:#"transform.scale"];
scaleAnimation.fromValue = [NSNumber numberWithFloat:fromScale];
scaleAnimation.toValue = [NSNumber numberWithFloat:toScale];
scaleAnimation.additive = YES;
scaleAnimation.removedOnCompletion = NO;
CAAnimationGroup* animationGroup = [CAAnimationGroup animation];
animationGroup.animations = [[NSMutableArray alloc] initWithObjects:panningAnimation,scaleAnimation, nil];
animationGroup.beginTime = 1e-100;
animationGroup.duration = 5.0;
animationGroup.removedOnCompletion = NO;
animationGroup.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
[imageLayer addAnimation:animationGroup forKey:nil];
return imageLayer;
}
Here is how i'm calling the method:
CALayer* animatedLayer = [self buildKenBurnsLayerWithImage:image startPoint:CGPointMake(100, 100) endPoint:CGPointMake(500, 500) fromScale:5.0 toScale:2.0];
The problem I am having is that the end result with panning and scaling is off by a few pixels on the screen.
If someone knows how to fix this i would great appreciate it.
All transformations are applied with respect to the anchor point. Try using the anchor point
CGPoint anchor = CGPointMake(0.5f, 0.5f);
Your "viewport" should no longer scale to the bottom right (if that is responsible for the animation being off by a few pixels), but equally to all directions.
so my current version looks like this: Animation Movie
i'm fairly new to core-animations, so what i try to achieve is that there are multiple points like the current one, moving from the left box in various angles, heights and speeds out of it, just like a tennis ball machine.
the first problem is, that my "ball" doesn't look like it gets grabbed from gravity and also the speed at first is not fast enough.
also, how to do this animation multiple times with variating distances between the beginning.
if something is unclear, PLEASE leave a comment.
my current code:
- (void)loadView {
[super loadView];
self.view.backgroundColor = [UIColor lightGrayColor];
CGPoint startPoint = CGPointMake(20, 300);
CGPoint endPoint = CGPointMake(300, 500);
UIBezierPath *trackPath = [UIBezierPath bezierPath];
[trackPath moveToPoint:startPoint];
[trackPath addQuadCurveToPoint:endPoint controlPoint:CGPointMake(endPoint.x, startPoint.y)];
CALayer *point = [CALayer layer];
point.bounds = CGRectMake(0, 0, 20.0, 20.0);
point.position = startPoint;
point.contents = (id)([UIImage imageNamed:#"point.png"].CGImage);
[self.view.layer addSublayer:point];
CAKeyframeAnimation *anim = [CAKeyframeAnimation animationWithKeyPath:#"position"];
anim.path = trackPath.CGPath;
anim.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
anim.repeatCount = HUGE_VALF;
anim.duration = 2.0;
[point addAnimation:anim forKey:#"movepoint"];
CALayer *caseLayer = [CALayer layer];
caseLayer.bounds = CGRectMake(0, 0, 140.0, 150.0);
caseLayer.position = startPoint;
caseLayer.contents = (id)([UIImage imageNamed:#"case.png"].CGImage);
[self.view.layer addSublayer:caseLayer];
}
Easiest way to model gravity is with those parabolic equations that you learn in basic physics. In short, the function below takes an initial position, a speed, and an angle (IN RADIANS, where 0 is to the right). a CALayer appears at position and gets shot at that speed and angle.
I'm using a CADisplayLink (which is effectively a timer that synchronizes with your frame rate) to call a function very quickly. Every time the function is called, the point is moved. The horizontal speed is constant and the vertical speed increases towards the bottom every frame to emulate gravity (`vy -= 0.5f; ). If you want more/less gravity, just mess around with this 0.5f value.
- (id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
point = [[CALayer alloc] init];
point.bounds = CGRectMake(0.0f, 0.0f, 10.0f, 10.0f);
point.backgroundColor = [UIColor redColor].CGColor;
point.position = CGPointMake(-10.0f, -10.0f);
[self.layer addSublayer:point];
[point release];
}
return self;
}
-(void)animateBallFrom:(CGPoint)start withSpeed:(CGFloat)speed andAngle:(CGFloat)angle
vx = speed*cos(angle);
vy = speed*sin(angle);
[CATransaction begin];
[CATransaction setDisableActions:YES];
point.position = start;
[CATransaction commit];
displayLink = [CADisplayLink displayLinkWithTarget:self selector:#selector(animate)];
[displayLink setFrameInterval:2];
[displayLink addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
}
-(void)animate {
if (point.position.x + point.bounds.size.width/2.0f < 0.0f || point.position.x > self.bounds.size.width + point.bounds.size.width/2.0f ||
point.position.y + point.bounds.size.height/2.0f < 0.0f || point.position.y > self.bounds.size.height + point.bounds.size.height/2.0f) {
[displayLink invalidate];
} else {
[CATransaction begin];
[CATransaction setDisableActions:YES];
point.position = CGPointMake(point.position.x+vx, point.position.y-vy);
vy -= 0.5f;
[CATransaction commit];
}
}
and the interface:
#interface Bounce : UIView {
CALayer *point;
CADisplayLink *displayLink;
CGFloat vx, vy;
}
-(void)animateBallFrom:(CGPoint)start withSpeed:(CGFloat)speed andAngle:(CGFloat)angle;
#end
I think there may be a couple of things you can do here.
- One is to use kCAMediaTimingFunctionLinear instead of kCAMediaTimingFunctionEaseOut.
- The other is to set your control point in the center of the ball's fall, wherever that may be. Try this:
CGPoint startPoint = CGPointMake(20, 300);
CGPoint controlPoint = CGPointMake(160, 400);
CGPoint endPoint = CGPointMake(300, 500);
UIBezierPath *trackPath = [UIBezierPath bezierPath];
[trackPath moveToPoint:startPoint];
[trackPath addQuadCurveToPoint:endPoint controlPoint:controlPoint];
CALayer *point = [CALayer layer];
point.bounds = CGRectMake(0, 0, 20.0, 20.0);
point.position = startPoint;
point.contents = (id)([UIImage imageNamed:#"point.png"].CGImage);
[self.view.layer addSublayer:point];
CAKeyframeAnimation *anim = [CAKeyframeAnimation animationWithKeyPath:#"position"];
anim.path = trackPath.CGPath;
anim.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
anim.repeatCount = HUGE_VALF;
anim.duration = 2.0;
[point addAnimation:anim forKey:#"movepoint"];
You should then be able to move the control point around for different paths.